The cool, beautiful Constance Schuyler lives alone in Manhattan in the early 1960s. At a literary party, she meets Sidney Klein, a professor of poetry twenty years her senior. Sidney is a single father with a poor marital record, and he pursues Constance with relentless determination. Eventually she surrenders, accepts his marriage proposal, and moves, with some dread, into his dark, book-filled apartment.

She can't settle in. She's tortured by memories of the bitterly unhappy childhood she spent with her father in a dilapidated house upstate. When she learns devastating new information about that past, Constance's fragile psyche suffers a profound shock. Her marriage, already tottering, threatens to collapse completely. Frightened, desperate and alone, Constance makes a disastrous decision, then looks on as her world rapidly falls apart. Her only consolation, as the city swelters in an interminable heat wave, is the friendship of Sidney's son Howard, a strange, delicate child, not unlike Constance herself.

The story of a marriage in crisis and a family haunted by trauma, Constance is also a tale of resilience and loyalty, and of the moral inspiration that can lead even the most lost of souls back to the light.